Backing-lumber for half-tones.



No. 841.115. PATENTED JAN. 15, 1907. W. BROWN & A. WEBER. BACKING LUMBERFOR HALF TONE-S.

APPLIUATION FILED A1E.17.1906.

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WILLIAM BROWN AND ALBERT WEBER, OF SAN FRANCISCO, CALIFORNIA.

BACKING-LUMBER FOR HALF-TONES.

Specification of Letters Patent.

Patented Jan. 15, 1907.

Application filed April 17, 1906. 'Serial No. 312,272.

T0 at whom it may concern.-

Be it known that we, WILLIAM BROWN and ALBERT WEBER, citizens of theUnited States, residing in the city and. county of San Francisco andState of California, have invented new and useful Improvements inBacking-Lumber for Half-Tones, of which the following is aspecification.

Our invention relates to backing for halftones, zincos, and the like.

The object of the present invention is to provide a cheap backing-lumberfor halftones, zincos, and the like which will not warp, which ismaintained in a non-warping condition by means other than metalreinforces, and which may be cut up into any size block and trimmed asdesired.

The invention consists of the parts and the construction and thecombination of parts, as hereinafter more fully described and claimed,having reference to the accompanying drawings, in which- Figure 1 is aperspective view of our improved backing-lumber, showing it with aalf-tone tacked on. .Fig. 2 is a perspective of a section ofbacking-lumber provided with screws, anchorages, and grooves. Fig. 3 isa perspective view of a section of backing-lumer provided with abacking-plate and a half-tone sweated to the backing-plate.

In carrying out our invention we take a board of suitable thickness andof any desired length and width. A represents such a board. Byboardwemeanwood, pulp, or any like suitable and cheap equivalent. This boardis mortised on both sides crosswise of the grain, with the mortises onone side alternating with those on the other and with the mortisespreferably a little deeper than half the thickness of the board. Intothese mortises are set the straight-grained wood strips 2, which areglued in or otherwise permanently secured in place, (except thatpreferably no tacks or nails are used,) and then the strips are planedofi flush with the top and bottom surfaces of the board. Thisconstitutes in its simplest form our lumber, which may be carried instock inany desired quantity and in any desired size of boards, thelatter to be cut up as needed into any desired size or sha e of blocksfor large, small, or medium hal -tones and zincos.

The cheapest of woods may be used in the manufacture of this lumber. Byinsertin the cross-strips 2 on both sides of the boar there is notendency, as we have amply demonstrated in practice, for the Wood towarp either way. If one takes a lain piece of Wood or ordinary woodenbacking-block, even though it is of the hardest and most expensive ofwoods, and tacks a half-tone onto it, it is only a short time before theblock becomes warped and buckles the half-tone. Also if the cross-strips2 are secured only to one side of the board the unbraced side will soonshow a tendency to curl at the edges or warp and cause trouble. Bymaking the mortises deeper than half the thickness of the board, so thatall the grains in the board are severed at frequent intervals, andemploying corresponding cross-strips We find that it improves thenon-warping qualities of the board.

The cross-strips on one side are arranged alternately and parallel withthose on the other for the purpose of enabling a board to be cut up intosmaller blocks, which Will not warp either.

The half-tone a or zinco or other printingplate may be secured direct tothe block by tacks b, as shown in Fig. 1, or by sweating the plate ontothe heads of screws 3, which latter are screwed into the board or block,as in Fig. 2. In this case the board after being mortised and tenoned,as previously described, is studded with screws or like metal inserts atsuitable intervals on one side, the screws being driven in flush withthe top surface of the board and arranged in symmetrical order, so asnot to interfere with the board being cut up into proper blocks. Thisconstruction may be used where it is desired to use our non-warping woodblock with such means to secure a plate thereto as will permit the blockand plate to be trimmed on all sides close up to the edge of the pictureor other printing matter on the plate. Where the plate is tacked directto the block thereisalways a narrow blank border left around the picturewhich is usually lost space.

In Fig. 3 is shown another modification of the invention in which ourmortised and tenoned board may have a soft-metal plate 4, about aneighth of an inch, more or less, in thickness, secured to its topsurface byscrews, nails, or other suitable means, and the halftone itmaybe tacked or sweated to this plate. This also enables the lumber tobe cut up into blocks and permits a block and plate to be trimmed.

It may be advisable under some conditions and with some kinds of Woodsto provide thetop surface of the mortised and ten- I plate and sooperate to maintain both sides of the wooden block at the sametemperature and subject to the same conditions of moisture and dryness.With the plain wood block and a plate secured direct to it the top ofthe block beneath the plate often gets very hot and dried out, while theunder side of the block absorbs moisture from the atmosphere. This isthe cause or one of the causes of the block warping and the platebuckling. The grooving of the block, as shown, tends to overcome thisdifficulty, and while it is not essential with our mortised and ten onedstructure it is nevertheless advantageous.

Having thus described our invention, what we claim, and desire to secureby Letters Patent, is- I 1. A backing-lumber for half-tones comprising aboard having transverse mortises on its two sides, tenons set into saidmortises flush with the surfaces of the board, said mortises and tenonsarranged to permit the board to be cut into smaller sections having thesame characteristics as the original board.

2. A non-warping backing-lumber for halftones, comprising a board havingtransverse mortises on its two sides, tenons set into said mortisesflush with the surfaces of the board, screws set ermanently into oneside of said board flusl i with the surface thereof, said screws,mortises and tenons arranged to permit the board to be cut into sectionshaving the same characteristics as the board itself.

3. A backing-lumber for half-tones comprising a board having transversemortises on its two sides, and tenons set into said mortises flush withthe board, said board having metal inserts at suitable intervals forminganchorages for the half-tones.

4. A non-war ping backing-lumber for halftones comprising a board havingtransverse mortises on its two sides, and tenons set into said mortisesflush with the board, said I11OI- tises on one side of the boardarranged alterrgately with those on the opposite side of the oar 5.Anon-warping backing-lumber for halftones comprising a board havingtransverse mortises on its two sides, tenons set into said mortisesfiush'with the board, said mortises on one side of the board arrangedalternately with those on the opposite side of the board, said mortisesand tenons having a depth greater than half the thickness of the board,and said mortised and tenoned board having shallow and narrow grooves onthe side which is to support the half-tone.

In testimony whereof we have hereunto set our hands in presence of twosubscribing witnesses.

WILLIAM BROWN. ALBERT WEBER.

Witnesseszl G110. T. KNOX, E. VERGEZ.

